The present disclosure generally relates to electrochemical machining, and more particularly, to methods and systems for performing electrochemical machining.
Electrochemical machining (ECM) is a process of removing electrically conductive material such as metallic materials by an electrochemical process. It is typically used for machining (working/finishing) a workpiece composed of an electrically conductive material. Generally, metals and alloys that have a high hardness and are difficult to machine with conventional methods, are machined using ECM. ECM generally provides desired shape control and a smooth surface finish for manufacturing the components, for example compressor airfoils such as blades for gas turbines, jet engines, and power generation.
During ECM process, the electrically conductive material is oxidized from the workpiece using an applied potential allowing a current to flow in an electrochemical cell at a controlled rate. The workpiece serves as an anode and is separated by a gap from a tool electrode, which serves as a cathode. The electrolyte, usually a salt solution in water, flows through the gap, flushing away the oxidized material from the workpiece. This electrolyte after use (or the used electrolyte) contains a quantity of metal ions, that have been precipitated out of the solution as oxides, hydrates, or hydroxides, and is often referred to as sludge. As the tool electrode moves towards the workpiece to maintain a controlled gap, the workpiece is machined into the complementary shape of the tool electrode.
In a typical ECM system, the used electrolyte containing the metal ions generated during the ECM process can be treated or cleaned for removing the metal ions from the used electrolyte. The treated or cleaned electrolyte may contain a reduced or minimal amount of metal ions and can be re-used, recycled or re-supplied to the ECM system for the subsequent ECM process.
Moreover, the ECM process can be performed in a macromachining mode or a micromachining mode for shaping or finishing a workpiece depending on the required material removal and geometric fidelity. The macromachining process may have the attribute of a high material removal rate, which involves bulk machining and is often used in shaping of a workpiece. The micromachining process may have better geometric control and surface finish compared to the macromachining process at the expense of speed i.e. material removal rate. However, an ECM system can typically be operated either in the macromachining mode or the micromachining mode because of the requirement of specific process parameters such as a gap between electrodes, a potential applied to electrodes for performing the macromachining process or the micromachining process, and the purity level of the electrolyte.